This application claims the priority benefit of Taiwan application serial no. 88122129, filed Dec. 16, 1999.
1. Field of the Invention
The invention relates in general to a method and an apparatus for rewriting functions and fonts of a monitor. More particularly, the invention relates to a method and an apparatus connected to a VGA card to achieve the rewriting operation of functions and fonts of a monitor via a VGA signal line.
2. Description of the Related Art
In a current monitor system, the monitor controller has to be switched while modifying the function or debugging the software, and thus consumes a lot of cost. In a more advanced monitor system, a read only memory including an erasable programmable read only memory is built in, so that by refreshing the read only memory, the modification of functions, software debugging or font alteration can be achieved.
FIG. 1 shows a block diagram for a circuit of conventional monitor function system. There are 8 VGA signal lines coupled to a VGA card, including a vertical synchronous signal line (Vsync), a horizontal synchronous signal line (Hsync), a serial data signal line (SDA), a serial clock signal line (SCL), a ground signal line (Gnd), a red signal line (R), a green signal line (G) and a blue signal line (B). Under the normal operation, a first jumper 24 connects the monitor controller 19 with the read only memory to the horizontal and vertical deflection apparatus 20. A second jumper 25 connects the monitor controller 19 with the read only memory to the on screen display circuit 50, and the power source jumper 23 connects the monitor controller 19 with the read only memory to 5V. The Hsync, Vsync, SDA, SCL and Gnd signals are coupled to the monitor controller 19 having the read only memory. According to the received signals and applying the program in the read only memory to drive the horizontal and vertical deflection apparatus 20, the vertical booster 30 and the horizontal booster 40 are controlled as the horizontal and vertical control of the CRT. On the other hand, the on-screen display circuit 50 is driven to control the image pre-amplifier to receive the R, G and B signals. Being pre-amplified, the signals are sent to the image amplifier 70, and displayed on the screen of the monitor.
When the functions of the monitor system is to be modified, the data of the read only memory in the monitor controller 19 is modified. This must be achieved by opening the enclosure of the monitor. The first and the second jumpers 24 and 25 are switched to connect the monitor controller 19 to the writing flat cable 80, and the power source jumper 23 connects the monitor controller 19 to 12V. The read only memory writer (indicated by the reference numeral 92 in FIG. 2) is coupled to the writing flat cable 80 to perform the new functions and new fonts of the monitor system.
FIG. 2 shows a block diagram of a conventional function rewritable monitor system. When the enclosure of the monitor 100 is opened, the writing flat cable 80 and the VGA signal lines 18 can be found on the monitor main circuit board 110. In the jumper area 22, the first, the second and the power source jumpers can be found and switched. The memory writing system 90 controls the read only memory writer 92 via the computer, and observes the writing status by the monitor 96. The read only memory writer 92 is coupled to the writing flat cable 80 to performing the rewriting by the computer, so as to achieve the refresh function of the monitor system.
To refresh the monitor system, conventionally, the enclosure of the monitor has to be opened to switch the jumpers to refresh the erasable programmable read only memory. It is very inconvenient and costs a lot of labor.
The invention provides an apparatus and a method for rewriting functions and fonts of a monitor. By directly using the VGA signal lines to transmit and write the programming data and fonts of the monitor controller to the electrical erasable programmable read only memory, the data refresh can be done.
The apparatus for rewriting functions and fonts of a monitor is briefly described as follows. The VGA signal lines are used to transmit write commands and write data. A detection apparatus is coupled to the VGA signal line. An activation apparatus is coupled to the detection apparatus to switch a vision path into a write path, and to receive the write data and the write data, so as to output the write commands and data from the write path. A read only memory write command decoding apparatus is coupled to the activation apparatus via the write path. The read only memory write command decoding apparatus judges the write command, so as to output the write commands and data while rewriting fonts. For function rewriting, the read only memory write command decoding apparatus transfers the write commands into erasable/read/write signals and the write data into address signals and data signals. A read only memory is coupled to the read only memory write command decoding apparatus, so as to refresh the data stored in the read only memory according to the address signals, the data signals and the erase/read/write signals.
A retrieving apparatus is coupled to the read only memory write command decoding apparatus and the activation apparatus to judge the refreshing status of the read only memory according to the address signals, the data signals and the erase/read/write signals. After refreshing, the write path is switched to the vision path by controlling the activation apparatus. A set of IIC circuit is coupled to the read only memory write command-decoding apparatus to receive the write commands and the write data while rewriting the fonts. An on-screen display circuit detection apparatus is coupled to the IIC circuit to detect and output the write commands and the write data. An on-screen display circuit activation apparatus is coupled to the on-screen display circuit detection apparatus to switch the signal path into the font write path, and to receive and output the write commands and the write data. The on-screen display circuit write command decoding apparatus couples the font write path to the on-screen display circuit activation apparatus. The on-screen display circuit write command decoding apparatus transfers the write commands into erase/read/write signals, and the write data into address signals and data signals. The on-screen display circuit font read only memory is coupled to the on-screen display circuit write command decoding apparatus to refresh the data stored in the monitor font read only memory according to the address signals, the data signals and the erase/read/write signals. An on-screen display circuit retrieving apparatus is coupled to the on-screen display circuit write command decoding apparatus and the on-screen display circuit activation apparatus, so as to judge the refreshing status of the read only memory according to the address signals, the data signals and the erase/read/write signals, and to switch the font write path into vision path by controlling the on-screen display circuit activation apparatus.
A method of rewriting functions and fonts of a monitor is also provided by the invention. In step (a), a comparison of a plurality of sequential series addresses is performed on a plurality of signals of a VGA signal line. A monitor in-system programming mode is set when the comparison of the sequential series addresses is correct in step (b). A write command is read and judged in step (c), when the write command is to withdraw the monitor in-system programming mode, the process is jumped back to step (a). When the write command is to rewrite the functions, the process goes to subsequent step (d), and when the write command is to rewrite the fonts, a subsequent step (e) is proceeded. In step (d), a write data is read and written into a memory, and the step (c) is followed. In step (e), an on-screen display circuit in system programming mode is set. In step (f), the fonts are read and written into a font memory. In step (g), the write command is read and written, and the step (f) is proceeded afterwards when the write command is to rewrite the fonts, or the step (e) is proceeded when the write command is to withdraw the on-screen display circuit in system programming mode.
Both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.